# Kestra vs Windmill API + MCP

> Kestra scores 63.6 (B) on agent readiness against Windmill API + MCP's 55.9 (C), and leads in 5 of 7 scored categories. Windmill API + MCP leads on security & auth. Both do automation workflows. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/kestra-vs-windmill
- Markdown: https://www.anchorterminal.com/compare/kestra-vs-windmill.md (~2,250 tokens)
- Slim: https://www.anchorterminal.com/compare/kestra-vs-windmill.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/kestra-vs-windmill.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Kestra scores 63.6 (B) on agent readiness against Windmill API + MCP's 55.9 (C), and leads in 5 of 7 scored categories. Windmill API + MCP leads on security & auth. Both do automation workflows.

- Kestra: grade B, 63.6/100, rank #351 of 842. Markdown https://www.anchorterminal.com/tools/kestra.md · JSON https://www.anchorterminal.com/api/v1/tools/kestra.json
- Windmill API + MCP: grade C, 55.9/100, rank #579 of 842. Markdown https://www.anchorterminal.com/tools/windmill.md · JSON https://www.anchorterminal.com/api/v1/tools/windmill.json

## Which one, for what

### Kestra (B)

Good for: Engineering and data teams that want declarative YAML flows with scripts in any language, run on their own infrastructure.

Ahead on:
- Reliability, 89 against 40
- Payments & pricing, 50 against 35
- Maintenance & community, 93 against 87

Watch for: The open-source edition has one basic-auth username and password. API tokens, service accounts, RBAC and audit logs need Enterprise or Cloud

### Windmill API + MCP (C)

Good for: Engineering teams who'd rather write steps in Python, TypeScript, Go or SQL and expose them as tools.

Ahead on:
- Security & auth, 60 against 41

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: The default MCP URL puts the token in `?token=` unless a superadmin turns that off


## Score by category

| Category | Weight | Kestra | Windmill API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 89 | 40 | Kestra +49 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 82 | 79 | Kestra +3 |
| Agent ergonomics | 13% (16.2 this run) | 73 | 73 | even |
| Security & auth | 14% (17.5 this run) | 41 | 60 | Windmill API + MCP +19 |
| Payments & pricing | 10% (12.5 this run) | 50 | 35 | Kestra +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 93 | 87 | Kestra +6 |
| Transparency & trust | 7% (8.8 this run) | 69 | 65 | Kestra +4 |
| Negative events | ≤15 | -7 | -5 | |
| **Total** | | **63.6 · B** | **55.9 · C** | |

## Facts side by side

| Fact | Kestra | Windmill API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Kestra Technologies | Windmill Labs |
| Hosted endpoint | no (local only) | `https://app.windmill.dev/api` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 (open-source server and SDK repository). Enterprise Edition and Kestra Cloud are commercial | AGPL-3.0 (core), Apache-2.0 (clients and OpenAPI), commercial for enterprise-only parts |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| Last release | 2026-10-05 | 2026-10-01 |
| Terms last updated | no document linked | couldn't be read |
| Privacy policy last updated | no document linked | no date given |
| Customer content may train models |  | couldn't be read |
| Terms restrict automated access |  | couldn't be read |
| Terms restrict benchmarking |  | couldn't be read |
| Terms or service can change without notice |  | couldn't be read |
| Arbitration or class-action waiver |  | couldn't be read |
| Popularity | 29k stars, 244 npm/wk, 170 PyPI/wk | 18k stars, 126k npm/wk, 218k PyPI/wk |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Kestra.** Kestra's open-source edition has a 216-operation OpenAPI spec, Markdown docs for agents and weekly patch releases on two long-term support lines. Its only credential is one basic-auth username and password with full access, and five critical advisories were published between March and September 2026, all fixed.

**Windmill API + MCP.** Token scopes down to a single script path, with expiry. The default MCP URL puts the token in `?token=` unless a superadmin turns that off.

## Before you call either

### Kestra

1. Run 2.0.5 or 1.3.42 or later. Earlier builds carry unauthenticated remote code execution advisories fixed in 1.3.38 and 2.0.3
2. Set `kestra.server.basic-auth` in the config file before first start. Without it the setup page is open to anyone who reaches the port
3. Put the tenant in the path. Open-source instances use `main`, as in `/api/v1/main/executions/{namespace}/{id}`
4. Send flow inputs as multipart form fields, and add `wait=true` to get the finished execution in the same call
5. Keep port 8081 off any shared network. The management endpoints there skip the API's basic auth

### Windmill API + MCP

1. Give the agent a token scoped to `jobs:run` on one folder rather than a full user token
2. Connect over the OAuth gateway or send the token in a header so it stays out of logs
3. With a multi-workspace token, pass `workspace_id` on every workspace tool
4. Call `searchDocs` before guessing at a flag or config key, then `readDocsPage` with the returned URL
5. Poll the job by ID after `runScriptByPath` for long jobs instead of waiting on the call

## Questions

### Which is better for AI agents, Kestra or Windmill API + MCP?

Kestra scores 63.6 (B) on agent readiness against Windmill API + MCP's 55.9 (C), and leads in 5 of 7 scored categories. Windmill API + MCP leads on security & auth.

### Do Kestra and Windmill API + MCP need an API key?

Both take an API key or an OAuth sign-in.

### Can an agent call Kestra and Windmill API + MCP without installing anything?

No hosted endpoint is listed for Kestra. Windmill API + MCP has a hosted endpoint at https://app.windmill.dev/api.

### Are Kestra and Windmill API + MCP open source?

Yes. Kestra is open source (Apache-2.0 (open-source server and SDK repository). Enterprise Edition and Kestra Cloud are commercial). Windmill API + MCP is open source (AGPL-3.0 (core), Apache-2.0 (clients and OpenAPI), commercial for enterprise-only parts).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/kestra-vs-windmill.json, and with the fewest tokens: https://www.anchorterminal.com/compare/kestra-vs-windmill.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "kestra", "b": "windmill"}`. From a terminal: `anchor compare kestra windmill`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/kestra.json and https://www.anchorterminal.com/api/v1/tools/windmill.json

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